The Tomato Chlorosis Criniviruses (ToCV) and Tomato yellow leaf curl Geminivirus (TYLCV), which naturally infecting and limited to the phloem, have caused a drastic reduction in tomato yield. The current study aims to determine the incidence of single and mixed viruses using biological, serological and molecular PCR methods in natural tomato plants. The incidence of mixed infection was found more frequently, followed by ToCV and TYLCV (42.3, 28.8, 17.8 in 2020 and 49.1, 29.7 and 19.1% in 2021, respectively). ToCV causes chlorosis, TYLCV causes leaf curl and yellowing, while mixed ToCV & TYLCV cause progress symptoms. By using the heat shock protein 70 (HSP70) and coat protein (CP) genes, ToCV and TYLCV isolates could be identified. These isolates were recorded in GenBank under accession codes "ON951644.1" and "OP265136.1" respectively. Host plants responded differently to severe and common disease density between ToCV and TYLCV. The transmitted whitefly could distinguish between ToCV and TYLCV within 15-20 minutes of the acquisition period. ToCV increases in fields with high whitefly populations, requiring further research to understand effects and reduce harm.

Cucumber production exposed to huge losses in Egypt and worldwide due to infection with Cucumber mosaic Cucumovirus (CMV). The current study focus on the impact of two Egyptian CMV isolates on metabolic and oxidative activities in cucumber plants. Two CMV isolates was obtained from cucurbitaceous crops and confirmed by DASELISA. Inoculated cucumber plants by infectious crude sap with two CMV isolates showed difference in external symptoms. The metabolic and biochemical components of cucumber plants were affected with two CMV isolates. The present study provided that, CMV infection caused a significant reduction in both photopigments and biochemical components while bioactive components (proline and phenol) and oxidative enzymes (POX, SOD, PPO and CAT) were increased significantly compared healthy ones. It was found that cucumberCMV isolate was more effective in metabolic and biochemical than Squash-CMV isolate.

In the present study, a trail to evaluate of Newcastle Disease (ND) antibodies levels after different vaccination programs was conducted on layer chickens. A total of 200 one day-old layer chicks (White Lohmann) were divided into five groups A, B, C, D and E. Birds in groups A, B and C were vaccinated with live vaccine by intraocular, intranasal and drinking water methods , respectively. On the other hand, groups D and E were kept as unvaccinated control groups. Vaccination performed at days 5, 18 and 28 by different routes for mentioned groups. Hemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) methods were used for assessment of antibodies titer at days 15, 25, 37 and 45. Results of HI and ELISA tests indicated that, the intranasal and the intraocular method have highest antibodies titers compared with the drinking water method. In this study, maternally derived antibodies specific to Newcastle Disease Virus (NDV) (IgY) were extracted by dextran sulfate method from collected eggs of vaccinated laying chickens . Antibodies specific to NDV (IgY) were detected in the egg yolk using HI test  . Data revealed that antibodies specific to NDV (IgY) were presented in high titers that confer protection during early weeks of life for hatching chicks. Data concluded that extraction of maternally derived specific antibodies from egg yolk will facilitate accurate monitoring of ND vaccination programmes.

Plant viruses cause serious disease of crop plants reducing both quality and quantity of final produce. Serological tests are used all over the world in laboratory and field based detection of plant viruses and they are of great indispensable importance in agricultural production; virus certification programs; agricultural quarantine and production of virus-free crops grown for processing or fresh market. Cross reaction between viruses and their strains antisera limits serological differentiation of viruses and their strains by enzyme-linked immunosorbent assay (ELISA). This study aims to characterize the antigenic property of Tomato mosaic virus ToMV coat protein by using some bioinformatic tools to analyze its gene. Therefore, new methods in antibody production could be used as equivalent to Mabs in its high specificity. ToMV isolate was confirmed by Transmission electron microscope and differential hosts and propagated on N. tabacum cv. Samson. Systemic infection was developed on N. tabacum cv. Samson and local infection on Datora metel; D. stramonium; N. glutinosa; Chenopodium amaranticolor; C. quinoa. ToMV was purified and used as immunizing agent for antiserum production. TEM showed rod shaped particles with 300 x 18 nm dimensions. The titer of produced antiserum was 1:1024 evaluated by microprecipitin test and indirect-ELISA. Coat protein gene was amplified by RT-PCR with expected size of (Approx. 500 bp). The PCR product was sequenced then the generated nucleotide sequence  was translated into 160 amino acids. The amino acid sequence of Five B-cell epitopes, of 14 amino acid residues each, were predicted. Identifying Bcell epitopes play an important role in vaccine design, immunodiagnostic tests, and antibody production. Therefore, computational tools for reliably predicting B-cell epitopes are studied.